It’s taken Metabones a while to get this one out of the door, and has naturally been one of the most anticipated adaptors. With the hugely successful release of the Panasonic GH4 many users have switched to the smaller sensor format, but still have a strong investment in Canon EF mount lenses.

Now, they can make full use of these lenses, without the downfall of a huge crop factor due to the smaller micro four third sensor.

Like all non-camera body specific Metabones speedboosters, the Micro Four Thirds to EF Speedbooster offers 0.71x optical reduction; converting your x2 (or x2.3 in 4K mode for GH4) crop factor down to x1.5 (x1.7-1.8in 4K mode for GH4). You also get an extra stop out of your lens. Lets look at how this affects a typical lens and camera combo.

A Micro Four Thirds camera will now produce similar* results to super35mm cameras like the C300, FS700, F55 or an APS-C DSLR like the 7D or D800.

*Each brand has a slightly different crop factor, for example Canons APS-C is 1.6, so all results differ.

The Canon EF mount is one many have embraced since the DSLR revolution. It goes without saying that all Canons video DSLRs use this mount, further more it’s popular adaption to many other mounts (Nikon, Contax, Leica R etc..) has made it a safe bet in adhering your entire lens lines to. As a result, many will be happy about this release as it’s opened up their existing lenses with a more familiar crop factor.

What’s more, many of Canons EF mount lenses provide superb IS (Image Stabilization) which the Micro Four Thirds to EF Speedbooster will support; this opens up a whole new level of opportunity for M4/3 users; grabbing a combo like the above GH4 and Canon 24-105mm lens gives you an incredible zoom range with IS and a constant aperture of f/2.8.

All third party EF-S mount lenses will fit. So the lovely Tokina 11-16mm and Sigma 18-35mm have now been made available if you were holding out for the Canon mount versions.

The list of current compatible and tested Canon EF mount lenses is relatively small of the Metabones site, but it’s early days so expect this to grow healthily in the near future and a few firmware updates to broaden compatibility with other same-mount lenses.

The mount currently retails at $599, putting it inline with many of Metabones other popular adaptors.